Between 1942 and 1943, during the regime of General Ion Antonescu, he served in the Ministry of Foreign Affairs of Romania as an embassy secretary. He went into exile when Soviet troops entered Romania in 1944. Arrested at the end of World War II by American troops, he eventually settled in France in 1948. A year later, he published the novel Ora 25 (in French: La vingt-cinquième heure; in English: The Twenty-Fifth Hour), written during his captivity.

Gheorghiu was ordained a priest of the Romanian Orthodox Church in Paris on May 23, 1963. In 1966, Patriarch Justinian awarded him the cross of the Romanian Patriarchate for his liturgical and literary activities.[citation needed]

Gheorghiu's best-known book depicts the plight of a naive Romanian young farmhand, Johann Moritz, under German, Soviet and American occupation of Central Europe. Johann is sent to a labor camp by a police captain who covets his wife, Suzanna. At first, he is tagged as "Jacob Moritz", a Jew. Then, he and fellow Jewish prisoners escape to Hungary, where he is interned as a citizen of an enemy country. The Hungarian government sends its foreign residents as Hungarian "voluntary workers to Nazi Germany". Later, "Moritz Ianos" is "rescued" by a Nazi officer who determines he is a perfect Aryan specimen, and forces him into service in the Waffen SS as a model for German propaganda. Imprisoned after the war, he is severely beaten by his Russian captors, then put on trial by Allied forces because of his work for the Nazis. Meanwhile, Traian, son of the priest Koruga who employed Moritz in their Romanian village, is a famous novelist and minor diplomat whose first internment comes when he is picked up as an enemy alien by the Yugoslavs. Once imprisoned, the two heroes begin an odyssey of torture and despair. Traian Koruga is deeply unsettled because what he sees as the machinism and inhumanity of the "Western technical society", where individuals are treated as members of a category. He was writing a book within a book, "The 25th Hour", about Johann Moritz and the ordeal awaiting mankind. In the end, Traian suicides in an American-Polish concentration camp, while Johann is forced by the Americans to choose between either enlisting in the army, just as World War III is about to start, or to be interned in a camp (as well as his family) as a citizen from an enemy country.

The book was published in French translation in 1949 and was not published in Romania until 2004.